Assuming the mail is still forwarded to Zimbra via SMTP you'll be fine. Any other routing or setup may not work. IF you can post some more specific details about what your planning we can make a more specific recommendation.

Looking for new beta users -> Co-Founder of Acompli. Previously worked at Zimbra (and Yahoo! & VMware) since 2005.

Assuming the mail is still forwarded to Zimbra via SMTP you'll be fine. Any other routing or setup may not work. IF you can post some more specific details about what your planning we can make a more specific recommendation.

Nope. Zimbra is a mailserver. The UI requires our back end. So at the very least you'd need to migrate IMAP to Zimbra then service IMAP and the Web UI from Zimbra. You could still use your MTA/Spam stuff but not sure why you'd want to since moving that to Zimbra would allow you to centralize the config and mgmt.

Looking for new beta users -> Co-Founder of Acompli. Previously worked at Zimbra (and Yahoo! & VMware) since 2005.